This invention relates to filament winding machines particularly, but not exclusively, intended for preparing structures such as pressure vessels, for example by the winding of filamentary reinforcement material onto a mandrel. The reinforcement material is normally embedded in a suitable matrix, and when the vessel is self-supporting, the mandrel is removed. Typical materials to be used with such a winding machine are glass or carbon fibre as the filamentary reinforcement material, and elastomeric or resin material for the matrix.
The invention is particularly concerned with a filament guide system for a filament winding machine.
Current filament winding machines are provided with a filament guide system which usually comprises a filament guide carriage arranged for rectilinear reciprocation along the machine parallel to the axis of the mandrel. The motion of the carriage is usually designed to be such that the filament is guided thereby onto the mandrel in a helical path along any cylindrical portion of the mandrel, and to follow an approximately geodetic path around each end of the mandrel. As the carriage reciprocates, the filament is laid onto the mandrel in a pattern which in due course provides even reinforcement over the mandrel surface in forming a strong body or the pressure vessel.
The carriage is provided with a drive mechanism to enable it to follow the required movements for the necessary pattern to be produced. The drive mechanism may comprise a yoke upon which the carriage is mounted, the yoke being linked to an endless chain traversing around a pair of rotating sprockets. The connection between the yoke and the chain is a guide pin which will move the yoke at a constant speed whilst on the horizontal flight between the two sprockets, and will then displace the yoke with simple harmonic motion whilst passing along the semi-circular path around each sprocket; in this part of the movement, the pin slides along a vertical slot in the yoke. The path to be followed by the carriage is dictated by the pattern required on the mandrel, and particularly for large diameter and low winding angle mandrels, this means that the sprockets have to be correspondingly large.
It will also be appreciated that for the same shape but different sizes of mandrels, substantial adjustment of the winding machine is required in that different sprocket sizes will be necessary together with different lengths of chain.
It is an object of the invention to provide a more versatile filament guide system for a filament winding machine.